1. Statement of the Technical Field
The invention concerns communications system. More particularly, the invention concerns systems and methods for compensation of beamforming errors in a communications system having widely spaced antenna elements.
2. Description of the Related Art
Multiple element antenna arrays are widely used in wireless communications systems to enhance the transmission and reception of signals. In particular, the enhanced performance is generally provided by using such antenna arrays in conjunction with beamforming techniques. Conventional beamforming takes advantage of interference between electromagnetic waves generated by each of the different antenna elements in the antenna array to change the overall directionality for the array. For example, during transmission, the phase and relative amplitude of the transmitted signal at each antenna element is adjusted, in order to create a desired pattern of constructive and destructive interference at the wavefront of the transmitted signal. During signal reception, the received signals are processed and the different antenna elements are arranged in such a way that a pre-defined pattern of radiation is preferentially observed by the antenna elements.
In general, such antenna arrays typically include a system controller, a plurality of antenna controllers, and a plurality of antenna elements (e.g., dish antennas). Each of the antenna elements is typically communicatively coupled to the system controller and a respective one of the antenna controllers via cables. During transmission and reception, each antenna element converts electrical signals into electromagnetic waves and vice versa. The system controller, using conventional beamforming techniques, varies the configuration of the various components in the antenna array to provide a particular radiation pattern during transmission or reception. However, as the dimensions of the array, the number of antenna elements, and the precision required in certain beamforming applications increases, properly concerting the actions of the various components becomes increasingly difficult.